On 14 December 2012 12:40, Harald Alvestrand <harald@alvestrand.no> wrote:
> Bernard mentioned a minimum gap (I think he said 50 ms), but I'm not sure
> where that came from.
Minimum values come from experience with IVR interoperation for cases
where the tone is subsequently mixed into the audio. Too short a tone
(or gap) and some IVRs fail to detect the tone. I've seen minimum
tone duration of 100ms and gap of 50ms in some cases, though more
conservative values might be appropriate. I have no good data to back
any specific choice. I expect fluffy has more data than I.